Endocrine disrupting compounds (EDCs) present in wastewater treatment plant (WWTP) effluents are a significant water quality issue. EDCs have been demonstrated to have adverse effects on aquatic life at extremely low concentrations. The synthetic estrogen, 17α-ethinylestradiol (EE2), is a particularly potent EDC of concern in WWTP effluents. Biological degradation is a critical mechanism for EDC removal in WWTPs. The goal of this research was to isolate and identify bacteria capable of degrading EE2 with an eventual goal of using the bacteria to improve WWTPs’ removal efficiencies. The experiments started with enrichments established in pH-buffered mineral salts media containing 1000 µg/L EE2 as the only added carbon and energy source, which were originally inoculated with activated sludge obtained from a local WWTP. Vitamin solutions were added to overcome loss of EE2 degradation abilities that were seen in earlier isolation attempts, and the new enrichments were monitored weekly for EE2 concentration using High-Performance Liquid Chromatograph with UV detection (HPLC-UV). Of the eight enrichments, three were found to degrade EE2 to below 200 µg/L within 54 days, as opposed to 120 days in the other enrichments. These were transferred to fresh media to reduce inactive bacteria concentrations through dilution and were monitored for degradation. Two of the three were transferred again after 78 days to fresh media and monitored for continued degradation. Transfer of the liquid cultures to solid media is currently underway to allow selection to single colony isolated cultures that can be assessed for their EE2 degradation abilities. This work is a promising advancement in the isolation of an EE2 degrader that will have a positive impact in bioaugmentation for the removal of EDCs from WWTP effluents.

Arsenic (As) is a human toxin and carcinogen that can be ingested by drinking contaminated groundwater or by eating crops that are irrigated with contaminated water. In the past decade, studies have shown that arsenic contamination poses a threat to global public health. Despite the health risks, few countries regulate the arsenic content of food. With this research project, my mentor and I hope to obtain information that will be valuable for the formation of appropriate regulations about arsenic content in rice. We have chosen rice because it is a staple of the diet in Bangladesh, which is currently experiencing an epidemic of arsenic poisoning. Specifically, we are studying how the diffusion of dissolved oxygen into the root-zone of rice plants affects arsenic accumulation in rice grains. We have been able to visualize these concentrations in real time using two-dimensional optical oxygen sensors (optodes) placed on the root zone. We have also measured the concentration of arsenic in the rice grains. Oxygen oxidizes dissolved iron(II) into solid-phase iron (III), which can scavenge arsenic out of solution and reduce plant exposure to arsenic. Twelve rice plants were studied, half grown in ambient temperatures and half in elevated temperatures to simulate a warmer climate. We chose to grow half the plants in elevated temperatures because many of the world’s rice producing regions are projected to experience warmer climates in the futures. Our data have provided valuable information about how dissolved oxygen concentrations near the roots of rice plants change temporally and spatially. Additionally, we've found that when grown in elevated soil temperatures, rice plants grow larger and have proportionately larger root systems. These larger plants require more water, and thus pull more arsenic from the soil porewater toward their root system, which ultimately results in greater uptake of arsenic and accumulation of arsenic in plant tissues.

Precasting concrete uses a controlled environment known as a precast plant to create concrete members more quickly and carefully than could be done on a construction site. Precasting is a huge industry innovation avoiding onsite complications. This process leads to better quality concrete products that are faster and cheaper to make. While this practice is already well established in industry, some of the more precise material properties are not exactly known, including the relationship between applied stresses and resulting displacements, known as the modulus of elasticity. Because plants accelerate curing using heating, material properties are affected and difficult to determine. To investigate modulus of elasticity, freshly poured concrete samples were subjected to heating, and the modulus of elasticity was measured and compared against unheated concrete samples more analogous to an onsite concrete pour. This was accomplished by using a compression testing machine applying controlled loads according to American Society  for Testing and Materials standards and recording the deformations of both heated and unheated samples. Testing occured at regular intervals up to 56 days after the concrete was poured in order to capture the time dependency of the modulus of elasticity as the concrete cured. With a fuller knowledge of this specific property, a material model will be created to better equip precast plants in predicting precast concrete behavior, such as intentional upward bending to resist eventual bending in the opposite direction. A more accurate model will also give a better idea about stress losses in prestressing cables, which strengthen concrete members by providing a clamping force to prevent cracking or failure. Cable stress changes when concrete deforms, and is also affected by heating. With an improved understanding of the material behavior during curing, precast plants will be better equipped to precisely manufacture the concrete products that make modern infrastructure possible.

Breaking waves dissipate energy in the form of turbulence and bubbles, and are important to many fundamental processes at the air-sea interface. Breaking waves are also a hazard to safe operations at sea and to the survivability of coastal structures. Recent buoys developed at the Applied Physics Lab are designed to study the dynamics of a breaking wave. The buoys are mounted with a number of instruments, including a camera pointed down at the surface of the water. Until now, there has been no useful, automated method to correlate these images with underwater measurements. Using MATLAB, I have produced an algorithm that analyzes the images taken by SWIFT drifters during deployment. Images with breaking waves and breaking rates during each deployment are outputted. I accomplish this through a ‘scoring’ system combining three image-processing techniques. The images go through brightness detection, searching for the signature white color encountered when a wave breaks, as well as through texture analysis. If the images pass certain thresholds for these analyses, points are awarded to their score. The images then pass through glare detection algorithms that remove points from their score if certain thresholds are met. This provides a method for identifying images, with various levels of certainty, which contain breaking waves. This method of scoring and a system of manual checks minimizes the number of false positives, increasing the algorithm accuracy. This algorithm is starting to be put to use on data sets, adding valuable information to current research at the APL. Much of the current area of study is the mouth of the Columbia River, on the Washington-Oregon border, but these devices have been deployed worldwide, including a study this summer in the Arctic Circle. Studying these breaking waves adds a wealth of information to coastal engineering applications and study of air-sea interactions.

Microbial growth can be monitored by changes in the optical density of a culture. In the past, these measurements were generally made by hand, one at a time at regular intervals, in order to produce a growth curve. Currently no such device is suitable for monitoring the growth of fastidious anaerobes. This presented problems for both efficiency and resolution of experiments requiring analysis of multiple cell lines and different growth conditions. For growth periods greater than a work day, researchers needed to take alternating shifts in order to capture data. This is a very tedious process which is draining on the tester. The result of such a worker demand was infrequent measurements to make the minimal curve, resulting in inherent tester bias. Naturally, the desire to automate the process arose. I began development on the ROGR system began in order to implement a microcontroller operated test setup using LEDs and phototransistors to replace the manual measurements made with a spectrophotometer. Previous work has shown that LEDs of these wavelengths do not interfere with cell growth. As this is an ongoing experiment, it is imperative that the method used to measure growth does not change the testing environment. For example, the anaerobic cultures have long been incubated with constant shaking with the culture tubes oriented in a horizontal plane, but measurements were made in the upright position in order to create an accurate reading. The ROGR is a multi-disciplinary project that addresses these project needs. The electronic design ensures system isolation and achieves high precision and dynamic range. Design also ensures mechanical stability, reducing error in LED phototransistor pairs readout originating from changes in their physical orientation. Presently the system is undergoing the physical implementation phase with its circuitry at a working state. This reproducable system will allow for data colection across multiple teams to be connected with confidence of small error.

From 1951 to 1981, the Canadian weathership program collected nearly continuous wind and wave observations at Station Papa, a common reference site in the North Pacific. The length of this time series makes it a valuable tool in determining long-term trends and statistics of North Pacific wind and waves. Due to the uncertain quality and poor documentation of the data, extensive cross-referencing and quality control of disparate data sources was performed, leading to the development of a single, high-quality dataset. To verify the accuracy and consistency of the weathership measurements, histograms of wind speed, wave height, and wave period were compared with those from modern wave buoy measurements at Station Papa, taken since 2010. While the wind measurements aligned well with the newer data, the wave observations showed notable biases. These biases are likely due to the outdated method of visually observing waves from the weatherships. A time-series model with an annual oscillation and autoregressive component was fit to the wind measurements. Such a model accurately represents both the seasonal weather cycle and short-term storm pattern at Station Papa. In addition, it was found that the wind and wave statistics were significantly correlated on interannual timescales with the El Niño Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO). Quantifying the impacts of these trends has practical implications for predicting future changes in wind and wave climate.

Thaumarchaeota are widespread in marine and terrestrial environments. Many of them are thought to carry genes coding for a putative ammonia monooxygenase (AMO), suggesting a capacity for ammonia oxidation. However, strong evidence from isotopic studies and molecular surveys, as well as direct physiological characterization shows some populations of ammonia-oxidizing archaea (AOA) have a capacity to use alternative fixed carbon for biosynthesis, and suggests their mixotrophic lifestyle. In this study, we investigate the influence of organic substrates on growth and activity of the only two available isolated representatives of marine AOA, Nitrosopumilus maritimus strain SCM1 and strain HCA1. The certain intermediates of the TCA cycle are supplemented into AOA pure cultures, and the growth response of each strain to different organic substrates are monitored by measuring nitrite production and cell counts. The calculated specific growth rate, doubling time and specific cell yields are compared between organic carbon amended cultures and organic carbon-free controls. The SCM1 and HCA1 growth rate and cell yield were greater in cultures supplemented with alpha ketoglutaric acid (from 93.4 to 112.6 x 1012 cells mol-1 NH4+ for SCM1, and no growth to 80.8 x 1012 cells mol-1 NH4+ for HCA1), which suggest that marine AOA may prefer a mixotrophic lifestyle. This data expands our knowledge of thaumarchaeal metabolic capabilities and can provide information on the competition between AOA and other microbial groups to improve our understanding of microbial ecology.

Ammonia-oxidizing archaea (AOA) are essential to the nitrogen cycle in the environment.  By processing ammonia into nitrite, AOA impact plant growth and other environmental factors such as greenhouse gas emissions and groundwater chemistry- mainly leaching of mobile nitrite and nitrate.  To optimize agricultural practices and minimize ecological impacts, a better understanding of the role of these microorganisms in the environment is needed.  AOA have been identified as the dominant nitrifying group at long-term agricultural study sites in eastern Washington.  Enrichment cultures of AOA have been established from these sites.  However, the relationship of the enriched populations to other AOA remains unknown. The goal of my research is to scale-up existing AOA enrichment cultures for nucleic acids extraction and molecular analyses.  Isolated DNA will be PCR amplified for phylogenetic and functional markers, mainly the 16S rRNA and ammonia monooxygenase subunit A gene, respectively.  These PCR products will then be cloned, sequenced, and compared to other AOA in public databases to assess their relationships with other populations.  These data will greatly aid in the design and interpretation of further physiology and environmental genomic surveys of AOA in the environment.

Unreliable freeway travel times are a growing source of frustration for drivers in metropolitan areas. Where factors prohibit the average travel times from being reduced, policy goals have shifted towards increasing reliability. Increasing reliability will allow drivers to budget their time more efficiently by reducing uncertainty. In order to characterize travel time reliability for a given roadway, research efforts are made to identify factors that cause variability in travel times and quantify their relative impacts. The factors studied include typical congestion patterns, roadway incident types and durations, and adverse weather conditions. These factors were chosen because typical congestion patterns may vary travel times over the course of a given day, while incidents and adverse weather conditions can make travel times at a given time of day difficult to predict. In order to measure the impact of these factors on reliability, this study calculated travel times using measurements from loop detectors embedded in roadways roughly every half a mile. Then, the calculated travel times were tagged with incident and weather data from existing databases, and with values for typical congestion based on the time of day. Finally, the travel time distribution for each set of conditions was determined to calculate their relative contributions to unreliability. Findings revealed that travel time reliability is the lowest during the most congested times of day, and that weather tends to decrease reliability more than incidents. In testing parallel corridors on I-5 and I-405 from Tukwila, WA to Lynnwood, WA, the study indicated that despite its higher capacity, I-5 is generally less reliable than I-405. Findings of this study will help transportation agencies identify solutions to improve travel time reliability on urban freeways.

The purpose of this research is to formulate an accurate, reliable, and efficient procedure for calculating wind loads on rooftop mounted photovoltaic systems. Current standards do not have any code regarding solar panels because they are relatively new. We are currently performing an in-depth analysis of photovoltaic systems located on the rooftop of Hogue Hall at Central Washington University. Full scale wind tunnel testing will also be performed by the Institute for Business and Home Safety at their research center in Chapel Hill, South Carolina. Weak points of mounting systems are identified and presented. Reasons for past failure of solar panels were investigated using structural analysis. In order to give the greatest chance of destruction of racking systems, hurricane force wind speeds were assumed. This study is assumed to take place in worst-case scenarios. We hope to have our procedure included in ASCE 7-16.

Underground structures are important in civil infrastructure in modern urban areas to address the growing need for space. They are used in a wide range of engineering applications including building foundations, underground transportation systems, and underground storage facilities. These shallow structures typically require soil excavation from the ground surface. Thus, stability of the excavated ground is a major challenge in the design and construction processes. Bracing approaches have been implemented in the current state-of-practice to ensure the safety of the excavation. One common “Braced Excavation” system involves vertical retaining walls on both sides of the excavated ground held in place using horizontal internal struts. These struts are designed using Peck’s method of pressure distribution envelopes, which considers the strength of the material (i.e. soil and steel) and soil lateral pressures. However, due to uncertainties involved in the material properties and estimation of the soil pressure, the design internal strut loads tend to be higher than the internal strut loads seen in real-world situations. The objective of the research was to compare the induced internal forces on the laterally resisting struts in a braced excavation system found by using Peck’s Method, and measured internal strut loads using centrifuge physical modeling. A target prototype braced excavation system was defined and designed based on Pecks method of pressure distribution envelopes. Then, a scaled physical model was constructed and employed to simulate the prototype system in a geotechnical centrifuge. The insight gained through this project will be valuable in performance-based design engineering of underground structures. In addition, it will provide a comparative assessment of the efficiency of the design procedures, which eventually will lead to lower factors of safety.